Experiment
by Lassroyale
Summary: Casey conducts an experiment with Chuck as the test subject - in a supply closet.


**A/N:** Written for chuck_slash: Slashy Sunday contest, which I missed by about four days. ::facepalm:: Anyway, the prompt was:

_"It started out with a kiss. How did it end up like this? It was only a kiss. It was only a kiss!"_  
(The Killers ~ Mr Brightside)

**Experiment **

**-VVV-**

It was an experiment.

That's what Casey had said at least: an experiment. _'Strictly business, Bartowski, don't get your panties in a twist.'_ Right, experiment then – that was Casey's story and he'd hold you at gunpoint if you said otherwise.

Chuck, who generally disliked being held at gunpoint, didn't say otherwise.

And yet…and _yet_, here Chuck was, jaw tilted slightly upwards with the knob to the supply closet door digging into his back, making some ridiculously helpless sounding noise as he learned that Casey kissed like a tactical strike. No, that was wrong. The NSA agent kissed like he was invading another country: there was precision there, sure, and _strategy_ too, yet mostly there was a kind of brute force that made Chuck feel like he'd been hit with nerve gas. Or something. Not that, you know, Chuck had ever been hit with nerve gas. (Of course Casey might have threatened him with it, one or two times.)

Chuck might have been able to buy the whole 'experiment' explanation, if this sort of quick, workplace fumble, (fumbling on his part, scarily competent groping on Casey's) had been a one-time deal. Except - as this was at least the fourth or fifth time he'd been yanked aside and kissed into submission by the other man - he was beginning to have his suspicions. After all, there was usually a control, an independent variable, and - _oh Christ on a cracker, he could not be thinking about variables of a scientific experiment while his dick was this hard. _He was certain there were laws against that kind of thing.

But still…

"C-Casey," he gasped out, managing to dredge enough blood back up to his brain to form the words. His lips felt plump, swollen and wet, maybe a little numb. His pants were very tight and Casey was a solid weight of flesh and muscle pressed up against him.

Casey stopped his ministrations almost immediately, which was rather unfortunate, and growled out a low, "What _is_ it, Bartowski?" He sounded annoyed; in fact, Chuck was a little annoyed with himself too because the things that Casey could do with his tongue were nothing short of masterful.

Masterful? Chuck almost rolled his eyes.. If he wasn't careful he'd be writing odes to the man's "masterful" tongue techniques in his diary. Not that he kept a diary or anything. Really – he didn't. He might keep a journal – journals were perfectly okay – but certainly not a _diary_. Teenage girls kept diaries and wrote dirty things about Taylor Lautner in them, certainly not grown men like Chuck. And no, he certainly did _not_ know who Taylor Lautner was, because in his book twilight was strictly a time of day.

"Thank god you're not Emma Frost," he muttered.

"What?"

Chuck snapped his attention back to Casey, who was staring at him in irritation beneath a lust-heavy gaze. Chuck could feel the blood begin to drain from his brain and shoot south; with effort, he managed to keep a hold of his train of thought. "Not that you'd be Emma Frost or anything," he blurted, jumpy beneath the heat and weight of Casey's stare. "Because you, well, you know, don't have a nice pair of breasts."

The crease between Casey's brows, deepened.

"But if you _did_ have breasts,' Chuck babbled on, picking at a bit of non-existent fuzz from the font of Casey's shirt, "I'm sure they'd be nice – wondrous – full and round and – "

Casey shut him up with another kiss that left Chuck's legs wobblier than a newborn fawn's. "Get to your point," Casey muttered against his mouth.

"Uh...my point?" repeated Chuck dazedly, before blinking a few times and sorting out the jumbled mess of his head. "Right, my point. Um, well," he looked away for a moment, keenly aware that his lips were tingling with residual heat from Casey's mouth, and said: "What sort of 'experiment' have you been conducting?"

Casey leaned back from him and simply smirked, much to Chuck's exasperation.

"So," he pressed, shifting, powerfully aware that he was about to have a potentially meaningful conversation while sporting a rather persistent hard-on, "what's the experiment? I mean, the first kiss was really…nice…and," he could feel heat creep into his face, "_hot_…wet..." Chuck trailed off, distrusting the scrutinizing expression that had fallen over Casey's features.

The big man leaned in, trailing his mouth along Chuck's cheek until he got to his ear. "The experiment, Bartowski, is to see how you react to different stimuli. For example –" Casey nibbled lightly on Chuck's ear, causing Chuck to shiver. Casey then placed a large hand against the small of Chuck's back and pressed his fingers lightly against his spine, while at the same time tilting his hips forward. Chuck groaned, sagging into the other man, panting when Casey rubbed his thigh against his clothed erection.

"F-fuck," he managed to say in response, breathing noisily.

Casey didn't stop there. "You whimper when I do this," he said, and Chuck was about to respond that, 'No, he certainly did _not whimper_, thankyouvermuch' when he was, goddamn it, when he was _whimpering_ against Casey's shoulder as the other man dipped his tongue into his ear and gently massaged the back of his neck with his free hand. Chuck felt every nerve ending light up with sensitivity, every inch of him wanting to be beneath Casey's palms; every inch of him wanting to be touched.

"Though the main reason I'm conducting these experiments," said Casey, turning his face to kiss the corner of Chuck's mouth, "is because it gets you to shut up for a good hour afterwards and I can get my damn work done." When Chuck began to reply indignantly, Casey simply swallowed his words with another thoroughly proficient kiss.

"That's not fair," Chuck mumbled a moment later, when he was able to catch his breath. "That's playing dirty."

Casey raised a brow. "I've found that it's the most efficient way to get a moment's peace," he said dryly. He paused, and then honest-to-god _grinned_ at Chuck. (And hell, that was always a bit terrifying.) "At least for a few hours."

"I'm much quieter after sex." Chuck felt the words slip out from between his teeth before he could stop himself. He grit his teeth, bracing himself for some sort of scathing come back, when Casey surprised him.

"You makin' an offer, Bartowski?" he growled, his gaze dark with want and desire and some other, very complicated emotions that made Chuck want to come in his pants without even touching himself. Casey stepped back into his personal space and braced his hands on either side of Chuck's head. "My place. Seven. Don't be late."

Then Casey was pushing back and shouldering Chuck out of the way as he yanked open the door to the supply closet, peering out methodically before striding off smoothly, like nothing _untoward_ had gone between him and Chuck for the better part of twenty minutes.

The door swung shut on Chuck's shocked face.

**-VVV-**

Casey's experiment yielded the hypothesized results (once again): Chuck remained eerily quiet for the rest of the workday. Still, he managed to make up for it - and then some - roughly half past seven, that night.

It was probably a good thing that Casey had seen fit to sound proof his entire apartment.

(The End.)


End file.
